RE: How to distinct the V2 and V3 IGMP query for a snoopingswitch?
"Ashish Yadav" <[email protected]>
| Newsgroups | gmane.ietf.magma |
|---|---|
| Message-ID | <[email protected]> |
In my view, IP does not include the padding of Ethernet in the length. Warm Regards, Ashish -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Tuesday, January 09, 2007 7:39 PM To: [email protected] Cc: [email protected] Subject: Re: [MAGMA]How to distinct the V2 and V3 IGMP query for a snoopingswitch? > According to the 7.1 of RFC3376 (IGMP V3) > 7.1. Query Version Distinctions > The IGMP version of a Membership Query message is determined as > follows: > IGMPv1 Query: length = 8 octets AND Max Resp Code field is zero > IGMPv2 Query: length = 8 octets AND Max Resp Code field is > non-zero > IGMPv3 Query: length >= 12 octets > I have a question about that. For Ethernet the IGMP V2 Query is > always encapsulated in a 64 bytes packet. da+sa+tpid+ip header+IGMP > query+padding+fcs=64 bytes,that means after 8 bytes Query fields,there > are some padding "zeros".For this packet the TOTAL LENGTH filed of IP > header is 46. So it seems that it's impossible for a snooping > switch to tell the IGMP QUERY > version from the IP header length. ... In my experience, the length in the Ethernet header does not include the padding bytes but I've found conflicting documentation on the web. _______________________________________________ magma mailing list [email protected] https://www1.ietf.org/mailman/listinfo/magma Conexant E-mail Firewall (Conexant.Com) made the following annotations--------------------------------------------------------------------- ********************** Legal Disclaimer **************************** "This email may contain confidential and privileged material for the sole use of the intended recipient. Any unauthorized review, use or distribution by others is strictly prohibited. If you have received the message in error, please advise the sender by reply email and delete the message. Thank you." ********************************************************************** ---------------------------------------------------------------------